Answer:
The correct answer is option 2.
Explanation:
Colligative property is defined as property which depends upon only on the numbers of particles of solute dissolved in definite amount of solvent, It do not depend on the nature of the solute.
For example : NaCl solution with 0.4 molal will show same colligative properties as a that of the glucose solution with 0.04 molal concentration.
The following are the examples of colligative property:
1. Relative lowering of vapor pressure.
2. Osmotic pressure
3. Elevation in boiling points
4. Depression in freezing point
Because the alkali metals are the group 1 metals, they have only 1 valence electron that they want to lose, and the halogens are the group 17 nonmetals, they want to gain 1 valence electron to become stable.
It will belong to the metals because metals bond with nonmetals like chlorine to form ionic compounds